Catalysts from hydrotalcite dopped with copper in chemical transformation of glycerol

• Autor(a) principal: SebastiÃo Junior Teixeira Vasconcelos
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
• Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14604
• topic: Ãxidos de HDLs; SÃtios bÃsicos; Desidrogenantes; Glicerol; HDL oxides; Basic sites; Dehydrogenants; FISICO-QUIMICA

The hydrotalcites are a class of layered double hydroxides with important physical and chemical properties. The use of this class of compounds in catalysis of specific reactions also requires many studies. The literature has exploited these materials in catalytic reactions in liquid phase with glycerol, particularly in hydrogenolysis reactions. The gas phase reactions with glycerol usually make use of acid catalysts. Thus, both the liquid phase reactions involving catalysts derived from hydrotalcite-like gas phase reactions involving basic catalysts require further study. We developed a study to elucidating the combined effects of basic catalytic sites (MgO and amorphous aluminum oxide) and dehydrogenation (derived from copper oxides) in the hydrogenolysis reaction. The materials used were derived from hydrotalcite oxides, and oxides derivatives containing in its composition 2.5% copper (molar ratio) in relation to the metal network hydrotalcite (Mg and Al). The results obtained for the gas phase show an interrelationship between the sites and the major products of the reaction, acetol and acrolein. Was determined conditions under which one or another product is more favored, with conversions that can reach over 90% and selectivities that exceed 99%. In the liquid phase this interrelationship is more difficult to be demonstrated, given the complications arising from the greater contact time between catalyst and reactants to the point of the major products at the reaction gas phase includes both as reaction intermediates in the liquid phase. In the liquid phase, the predominant carbon chain compounds of higher alcohol and ester functional groups, cyclic compounds but also from various functional groups.